The present invention generally relates to a selective calling reception apparatus, and particularly relates to an oscillator circuit for use in a selective calling reception apparatus in which current consumption can be reduced.
Conventionally, such a selective calling reception apparatus does not have a plurality of oscillators including an oscillator for intermittent reception and an oscillator for signal processing, but has such a configuration as shown in FIG. 4, in which a decoder 6 has a timing generation circuit 2, an intermittent reception control portion 3, and a signal processing control portion 4, so that the intermittent reception control portion 3 is driven by an intermittent reception driving signal b generated by the timing generation circuit 2 which is driven by a clock a generated by a single oscillator 1, and the signal processing control portion 4 is driven by a signal processing driving signal c generated by the timing generation circuit 2 and a signal processing timing signal d generated by the intermittent reception control portion 3 to thereby take a selective calling signal (hereinafter, referred to as an NRZ signal) from a base station into the signal processing control portion 4 as a reception signal.
In the conventional selective calling reception apparatus as described above, however, when the transmission rate of the reception NRZ signal is made high, it is necessary to make the oscillation frequency of the oscillator high in proportion to the transmission rate to thereby keep the resolution for the reception NRZ signal. There has been therefore a problem that if the oscillation frequency of the oscillator is made high in proportion to the transmission rate as described above, the oscillation current increases due to the characteristics of the oscillator to increase power consumption in the stand-by time in the selective calling reception apparatus to thereby shorten the battery life. There has been a further problem that it is necessary to keep the precision of oscillation to the same extent as that before the oscillation frequency is made high.